Pulp-cooking apparatus



n 1927. e I c. H. ALLEN PULP cooxme APPARATUS Original Filed Jan; 26,1923 3 Sheets-Sheet l @1 J. fnvgntor.

flany June 3 21, 1927. 1,633,554"

C. H. ALLEN PULP COOKING APPARATUS Original Filed Jan. 26, 1923 3 SheetsSheet 2 n 1927. e c. H. ALLEN PULP COOKING APPARATUS Original Filed Jan. 26,

1923 3 Sheets-Sheet 3 Inventor." W m Z; all.

Patented June 21, 1927. I

UNITED STATES 1,633,554 PATENT OFFICE.

CARLTON H. ALLEN, OF DAYTON, OHIO, .ASQIGNOB OI ON E-HALF T O GREAT NORTHERN PAPER COMPANY, 01" MILLINOCKET,

MAINE, CORPORATION 01 MAINE.

rum-booms Arrun'rus.

Application filed as, 1923, Serial 1n. 615,034. Renewed Iovember 20, 1920.

This invention relates to apparatus for automatically cooking pulp,'and more especially to mechanism for controlling the flow of steam in such apparatus.

In my co-pending application, Serial No. 530,140, filed January 18, 1922,, I have disclosed a pulp cooking apparatus in which the flow of steam is automatically controlled so that a substantially predetermined rate of flow is maintained, this flow being varied in a predetermined manner at successive intervals of time as the cookingoperation progresses. This apparatus has proved very satisfactory indeed in practice, producing a more uniform and better yield of pulp, re-

ducing the labor required, and distributing:

the steam load more evenly, and the preseut invention aims to further improve and perfect this type of apparatus with a view to-enabling it to handle automatically a wider range of conditions, especially unusual or abnormal conditions which may arise.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure 1 is a view, somewhat diagrammatic, illustrating a pulp cooking or digesting apparatus including features embodying.

the present invention;

Fig. 2 is a side elevation of the parts of this apparatus with which the present invention is more directly concerned, certain of the parts being shown in cross section;

Fig. 8 is a perspective View of a pawl and ratchet mechanism which form part of the apparatus shown in Fig. 2; and

Fig. 4 is a perspective View showing cer-,

tain details of the apparatus shown in Figs.

1 and 2.

Referring first to Fig.1, the construction shown comprises a digester 2, which may be of the usual type, and means for supplying steam to said digester including a steam supply line 3, a valve 4 controlling the flow of steam through said line, and an automatic mechanism described in detail below for operating said valve. The steam supply line delivers steam to the lower end of the digester 2, and a drain pipe 5 is connected to this end of the digester through a valve 6. A discharge pipe 7 leads from the upper Referring more particularlyto Figs. 2,3 I

and 4, it will be seen that the valve 4 com prises a movable valve element or lunger -10 of the balanced type, the areas of t 1e opposite ends of this element, however, being so pro portioned that the valve has a constant'tendency to close when steam is flowing through it. The valve stem includes a section 12 having a threaded engagement with a bracket 11, and also havin a telescoping connection with another sectlon 13, these'two sections being splined together so that theyv are compelled to rotate in unison but can have a relative longitudinal :movement. A bevel gear 14 is secured fastv on the upper end of" the section 13 and meshes'with another bevel gear 15 fast on one end of a horizontal shaft 16 which carries a worm' gear 17 meshing with a worm 18 fast on the shaft 19, Fig. 2.

These shafts and the parts 12 and 13 are all supported in suitable bearings. The" shaft 19 carries a wheel 20, best shown in Fig. 3, having a series of pins 21 projecting forward from the face thereof.

It is evident that rotation of the pin wheel 20 in either directionwill be transmitted throu 'the mechanism just described to the valve stem, and that therotation of this stem will raise or lower the valve plunger 10, depending upon the direction of such rotation.

For the purpose of producing this rotative movement ofthe pi'n wheel 20, a double acting pawl 22 is provided, this pawl including oppositely directed dogs 23 and 24, either of which may be made toengage the pins 21. This pawl has an arm 25 which is connected to the lower end of a crank arm .by a rod 37 which is connected to a bell crank lever 38, one arm of this lever being weighted while the other arm normally bears against a horizontal rod 41 sup rted in suitable guides for longitudinal siding movement. The weight 40 is suflicient, when it is. free to controlthe pawl 22, .to

hold this pawl in its right-hand position where it will cause a counter-clockwise rotation of the pin wheel 20. This operates through the connections above described to produce a step by step closing movement of the valve plunger 10.

The mounting of the pawl enables it to be moved into either a right or left position, or into an intermediate, neutral position in which it merely reciprocates/idly. A joint. control is exerted over this valve operating mechanism by a time mechanism and a mechanism which is responsive automatically to changes in the rate of steam flow. The time mechanism includes the 'motor 35 and a series of worm gear connections between the shaft of this motor and an upright screw threaded shaft 48. This shaft carries a nut 'or follower to which a cont-roller plate 51 is removably connected. This plate can swing freely on the nut 50 and its edge normally bears against the lefthand end of the rod 41, .Fig. 2. As the shaft 48 rotates, the nut or follower 50 rises carrying the controller 51 with it.

The mechanism responsive to variations in steam flow comprises a beam 55, best shown in Fig. 1, fast one shaft 56 which is mounte on knife "edge bearings. Two receptacles 58 and 59 are supported on opposite ends of the beam, the bottoms of the two receptacles being connected by a pipe 60, and the lower receptacle 58 and the pipe connection is filled with. mercury, or some other relatively heavy non-volatile liquid. A spring 61 normally holds the beam in the position in which it appears in Figs. 2 and 4. The upper ends of the two receptacles are connected to two Pitot tubes 64 and 65, respectively, located in the steam conduit or pipe 63, the connections between these tubes and the receptacles being clearly or follower 51 is thus tends to force the roll 80 and the shown in Fig. 4. Adjustably secured to the end of the shaft 56, but fast therewith, is an arm 80 carrying a grooved roll 81 at its free end, this roll bearing against the controller 51 at a point directly opposite the point of engagement therewith of the rod 41.

When the apparatus is in operation the differential pressure between the Pitot tubes 64 and is imposed upon the body of mercuryin the connected receptacles 58 and 59 and tends to force mercury out of the receptacle 58 into the receptacle 59. Obviously the quantity of mercury so transferred from one receptacle to the other will depend upon the difference in pressure between the Pitot tubes, and this differential pressure varies with the square of the veocity of the steam flowing through the pipe 63. As the shaft 48. rotates, the slide drawn upwardly and end of the rod 41 away from each other.

This results in shifting the position of the pawl 22 in a direction to produce an opening movement ofg the valve plunger 10, thereby increasing the flowof steam and the differential pressure ion the" l itot tubes 64 and 65, and consequently forcing mercury from the vessel 58 ".to the coi'itainer 59. This tips the beam 55 in a direction'to move theroll 81 away front the end of the rod 41. When the rate of steam flow has been increased to the degree predetermined by the contour of the controller 51, the roll 81 will swing slightly away from the edge of the controller plate, and the weight 40 will then move the rod 4:1 backward or to the left, Fig. 2, and return the pawl 22 to its neutral position. If the parts continue to move in this direction the pawl will be shifted far enough to initiate a closing movement of the valve 10.

The rate of steam flow thus will be varied at successive periods of time in accordance with the shape of the controller 51. Usually a relatively large steam flow is desired during the early stages of the cooking of a charge, and the flow is gradually reduced as the cooking operation progresses. When the end'of the controller plate is withdrawn from between the parts 81 and 11, the flow ,of steam will be automatically shut off, as

willreadily be understood.

The construction and operation of the apparatus as above described is substantially like that shown and described in my earlier application above designated. As previously stated, sulphur-dioxid gas is released very rapidly within the digester as the cooking operation proceeds, and heretofore the automatic pressure relief valve 8 has been depended upon to relieve the pressure automatically when it rises above a predeter-. mined point. It sometimes happens, however, that the relief valve docs not function properly, or the outlet from the digester to the pipe 7 becomes plugged, notwithstanding the presence of special screens in this outlet, and under suchcircumstances the pressure may rise within the digester to a dangerous point. This rise in pressure tends to reduce the rate of flow of steam through the steam line 3, and the automatic apparatus above described consequently acts atthis time to open the valve 10 wider 1n 7 order to maintain the rate of steam flow at the predetermined value. Pressure conditions within the digester therefore, tend to go from bad to worse. The present invention provides an additional controlling apparatus for the valve operating mechanism above described whichwill automatically effect the closing of the valve under these circumstances. This control, like those above described, is effected through the pawl 22.

Referring more particularly to Fig. 2, it

will be seen that the apparatus provided for this purpose comprises a casing in which is mounted a diaphragm or piston, one side of which is subjected, through a pipe connection 91, to the pressure in the steam line 3 at a point near the digester, this pressure being approximately equal to that in the digester. The pressure so exerted on the diaphragm is opposed by a weighted lever 92 acting on the diaphragm through a rod or stem 93. A rod 9% is pivoted at 95 and arranged to bear against the rod 37 previously referred to. Secured to, or formed integral with, this rod 94 is an arm 96 having a weight 97 adjustably mounted thereon, the two parts 94: and 96 forming, in effect, a bell crank lever. A wire or rod 98 connects the arm 96 with one end of a lever 99, the opposite end of which is connected by a rod 100 to the weighted arm 92 previously referred to.

So long as the pressure remains below the point for which the apparatus is set, the arm 94 will be held out of contact with the rod 37, and this additional controlling mecha-- nism' will have no effect on the operation of the other controlling mechanisms above described. When the pressure rises sufliciently,'however, the lever 92 will be lifted, thus allowing the weight 97 to swing the arm 9% against the rod 37 and cause this rod to move the pawl 2 towardthe right, Fig. 2, far

enough to initiate the closing movement of the valve in the manner above described. If the pressure conditions are not corrected, the result will be to closethe valve 10 completely.

If, however; the conditions which have caused the interruption of flow of fluids from the digester are corrected so that the normal discharge takes place, or the pressure conditions within the digester are corrected by any other means, the result will be to automatically reverse the operations just described. That is, the lever 92 will drop far enough to swing the arm 9 L out of contact with the rod 37 and thus allow the time and flow operated mechanisms to resume their normal control over the valve 10.

The invention thus provides an automatic safety controlling mechanism which normally has no effect whatever on the operation of the apparatus that controls the steam' flow, this flow being varied automatically by the controller plate 51 in exactly the same Way that it would be if the additional apparatus provided by this invention were not used. When the pressure within the digester, however, rises to a point above that desired, the mechanism just described comes into operation automatically, dominating the mechanisms which normally control the apparatus, and assuming control of the double acting pawl 22. It retains this control until the conditions which brought the in combination, a digester, asteam line leadmg to said digester for supplyingsteam thereto, and automatic means {torcontroh hug the flow of steam through said line jointly in accordance with the rate-of steam flow and the pressure conditions infsaid di gester.

2. A pulp cooking apparatus comprising, in combination, a digester, a steam line'leading to said digcstcr for supplying steam thereto, automatic means for c'ontrollingt'he flow of steam through said line to maintain a substantially predetermined rate of steam flow therethrough during a given period of time, and additional means for automatically cutting off said flow of steam when the pressure in said digester rises above a predetermined point.

3. A pulp cooking apparatus eomprisin in con'ibination, a digester, a steam line lear ing to said digester for supplying steam thereto, a valve controlling the flow of steam through said line, mechanism for operating said valve automatically to maintain a substantially predetermined rate ofsteam flow through said line, and additional mechanism for controlling said valve in accordance with the pressure conditions in said digester.

4. A pulp cooking apparatus comprising.

in combination, a digester, a steam line leading to said digester for supplying steam thereto, a valve controlling the flow of steam through said line, mechanism for operating said valve to open or close it, controlling means for said mechanism operative automatically to maintain a substantially predetermined rate of steam flow through said line while the pulp cooking operation progresses, and additional mechanism cooperating with said valve to enable it to control the flow of steam in accordance with pressure conditions in said digester.

5. A pulp cooking apparatus comprising, in combination, a digester, a steam line leading to said digestei for .supplying'steam thereto, a valve controlling the flow of steam through said line, mechanism for operating said valve to open or close it, controlling means for said mechanism operative automatically to maintain a substantially prede-- termined rate of steam flow through said. line while the pulp cooking operation progrosses, and additional controlling means for said mechanism operative to cause said valve to close when the dpressure in said digester rises above a pre etermined point.

6. An apparatus for controlling the flow of steam comprising, in combination, a valve, mechanism for operating said valve,

controlling means for said mechanism operative automaticallv to cause said valve to maintain a substantial] v predetermined rate of flow of steam theret rough, and an additional controlling means for said mechanism. t v

7. An apparatus for controlling the flow of steam comprising, in combination, a valve, mechanism for operating said valve,

f controlling means for said mechanism operated jointly. by a time element and by the rate of flow of steam,- and a pressure oper-' ated controlling means for said mocha-nism..

SQAnapparatus for controlling the flow of steam comprismg, in combination, a

valve, power driven mechanism for operating said valve, said mechanism including an actuating element operative to cause either an opening or closing movement of the valve, and pressure responsive means controlling the operation of said element.

9. An apparatus for controlling the flow valve, ower driven mechanism for operat-v ing said valve, said mechanism including an actuating element operative to cause either an opening or closing movement of the valve, means responsive to'changes in the rate of steam flow for controlling the operation of said element, and additional means responsive to changes in steam pres,-

: sure to control the operation of said element;

10. An apparatus for controlling the flow I of steam comprising, in combination, a

- one operative position to another.

. 11. An apparatus for controlling the flow of steam, comprising, in combination, a valve, power driven mechanism for'operating said valve, said mechanism including a constantly operated actuating element movable into different operative positions and connections arranged tobe actuated by said element to either'close or open the valve deof steam comprising, in combination, av

pending upon the position of said element, means responsive to changes in the rate-of steam flow for shifting said element from one operative position to another, and;adlitional means operative to (LSSLIIHByCOHtIOI automatically of said element when predetermined pressure conditions occur.

12. In an apparatus for controlling the fiowof steam, the combination with a valve and power driven mechanism for operating said valve including a double acting pawl movable into different operative positions;

and power driven mechanism for operating said valve including a double acting a wheel arranged to be given a step byjstep motion in either-direction by said pawl and connections for transmitting motion' from saidwheel to said valve, of automatic mechanism for controlling the position of said a-wl movable into, diti'ercnt operative positions,

pawl and operated jointly by a time element a and by the rate of flow of steam, and an additional mechanism for controlling the position of said pawl, said additional mechanism being normallyinactive but arranged ,to assume control over said pawl when prev determined pressure" changes occur and to restore said pawl to thecontrol of said automatic mechanism again when said pressure conditions are corrected; I

14. An apparatus for controlling the flow of steam comprising, in combination, a valve, power driven mechanism for operating said valve, said mechanism including a constantly operated actuating element movable into diii'erent operative positions and connections arranged to be actuated by said element to either close or open the valve depending npon the position of said element, an automatic mechanism normally controlling the position of said element and including a removably mounted controller, and a pressure operated mechanism connected with said elcment'and arranged to assume control over the position of said element when certain predetermined pressure conditions occur.

' CARLTON H. ALLEN. 

